The present invention relates to an arrangement and to a method for testing the tightness of a container, in particular in the context of a quality test on packaging containers.
In the context of a quality test on closed containers, a tightness test with excess pressure or with a reduced pressure is used as a technical method. Particularly in the area of medicament packages, tightness testing is indispensable. For this purpose, the container is arranged in a testing chamber, which is put under a vacuum. A pressure rise per unit time is then measured in the vacuum zone. If the vacuum pressure remains constant or equal to a tight reference component, this is an indication of the tightness of the container. If the vacuum pressure rises during the measurement time, this is an indication, in the case of a tight testing chamber, that the container is not tight. In the same way, a reduction in the excess pressure in the testing chamber is an indication of a container that is not tight in the case of a chamber under excess pressure. However, one problem in measuring the absolute pressure level is that, the smaller the existing leaks in the container, the smaller is also the leakage flow which is present at the pressure difference built up between the interior of the container and the testing chamber. Since an achievable reduced pressure level and hence also a pressure difference is technically limited by the leak, it is possible either to work with very long measurement times or, alternatively, with very precise, expensive pressure sensors. EP 0313678 B1 furthermore discloses a method and an arrangement for testing the tightness of a hollow body in a testing chamber, in which a pressure difference is measured and evaluated by means of a differential pressure sensor between a reference pressure system and the testing chamber. It would therefore be desirable to have an improved and, in particular, more compact and technically simple, solution for testing the tightness of a container.